It has been estimated that as much as 20% of the elderly population in the United States may be suffering from peripheral neuropathies, largely as a consequence of diabetes. Peripheral neuropathic patients exhibit increased body sway during quiet standing. Peripheral neuropathies have been associated with increased thresholds for the perception of ankle inversion/eversion and a reduced ability to maintain a unipedal (single footed) stance, suggesting a reduction in balance control while walking. Epidemiological evidence has linked peripheral neuropathies with an increased risk of falling. Postural responses to floor perturbations in peripheral (diabetic) neuropathy patients are delayed and are poorly scaled to the perturbation amplitude
The most common symptom of peripheral neuropathies is a reduction in sensation from the soles of the feet. A number of studies have provided evidence that afferent information from the feet is an important part of the balance control system. A recent study on adaptation to microgravity suggests that foot sole pressure may be critical for triggering the anticipatory postural adjustments that are normally required to maintain balance during arm movements.
For the above reasons and others, it would be desirable to have a sensory substitution system that effectively provides information regarding foot sole pressure distribution patients who are no longer able to acquire this information by natural means. The system should enable a patient wearing a device to achieve improved upright balance control, thereby reducing the patient's risk of falls and associated injuries. Such a system should further advantageously support integration of balance related feedback into the patient's unconscious postural control system, eventually eliminating the need for conscious effort in this regard.